Significant agreements - Ionis Evaluation and Option Agreement (Details) - USD ($) $ in Thousands		1 Months Ended
	Jul. 09, 2021	Jan. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue			$ 135,194	$ 61,873	$ 71,340
Ionis Evaluation and Option Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment	$ 3,000	$ 3,000
Deferred revenue						$ 3,000